1. Field of the Invention
This invention relates generally to bags and methods of making the same and, more particularly, to bags of the leakproof type having a rectangular end construction.
2. Description of the Prior Art
Bags of the indicated type are disclosed in U.S. Pat Nos. 2,496,796, 3,017,069, 3,342,402, 4,490,131, and 4,496,674. As disclosed in these patents, bags of this type generally comprise an outer sheet of paper and an inner liner of an impervious heat sealable material such as a plastic (synthetic resin). The bag is made of a tube and the bottom end of the bag is formed by making a diamond fold comprising a triangular fold portion and a partly rectangular tab fold portion. After the triangular fold portion and tab fold portion are sealed, the bottom of the bag is completed by folding over the tab fold portion onto a previously folded over triangular fold portion. The tab fold portion is caused to adhere to the bottom of the bag by applying suitable adhesive between the contiguous faces of the tab fold portion of the bag bottom structure. During this bottom forming procedure, the bag and the liner are in contiguous overlapping relation so as to form a single bottom structure having a two-ply configuration.
While the bags of the prior art are suitable in many applications, they have some limitations when they are used as containers for products such as pet food, coffee, or similar granular products and the like. For example, these products are typically packaged in "square-bottom" bags which have a pinched-top type of closure whereby there is a significant amount of unused "dead space", as referred to in the art. Thus, when these bags are stored on shelves, they are often stored in a non-upright position whereby they get crushed and lose their visual appeal to customers, particularly with respect to the display of the graphics thereon.